In a key settlement that will resolve all environmentally based legal challenges against its 600-MW ultrasupercritical John W. Turk Jr. power plant under construction near Texarkana, Ark., Southwestern Electric Power Co. (SWEPCO) on Thursday agreed to several conditions, including phasing out a 528-MW coal-fired unit in Texas, building 400 MW of renewable power, and limiting new transmission lines in natural areas.

The settlement between the American Electric Power (AEP) subsidiary and the Sierra Club, the National Audubon Society, and Audubon Arkansas ends a four-year high-profile public battle over the construction of the Turk coal-fired power plant in southwest Arkansas. The power plant under construction in Hempstead County is more than 80% complete. When commercially operational in late 2012, it will become the nation’s first coal plant to use ultrasupercritical technology.

SWEPCO and the environmental groups filed a consent decree on Thursday in U.S. District Court for the Western District of Arkansas in Texarkana that, if approved, will dismiss all other challenges made against the plant at other courts and regulatory bodies. “The settlement resolves all issues raised by the groups’ combined or individual challenges to the Corps of Engineers Section 404 permit, the air and wastewater permits issued for the plant, as well as a complaint recently filed at the Arkansas Public Service Commission,” SWEPCO said in a statement.

Under the settlement, a preliminary injunction in place in the federal district court will be lifted, allowing work to be completed on the advanced coal plant’s water intake structure and transmission river crossings.

Among a long list of conditions, the environmental groups demanded that AEP not build any new generating units at the Turk site and, as long as the Turk Plant is operational, that AEP not build any coal-fired units at any location in Arkansas within 30 miles of the Turk site. SWEPCO also agreed to combust only coal from the Powder River Basin in Wyoming or subbituminous coal with similar sulfur characteristics.

As soon as the Turk Plant begins operation, AEP will limit its coal-fired Welsh 2 unit near Pittsburg, Texas, to no more than 60% of its annual capacity. The utility also agreed to seek regulatory approval to retire the 1980-built unit by Dec. 31, 2014. This date will be extended to Dec. 30, 2016, if SWEPCO needs to complete transmission mitigation work related to the unit’s retirement. The Southwest Power Pool will determine the date of closure.

SWEPCO also pledged to build or secure 400 MW of renewable power. Under the settlement, a condition imposed by the National Audubon Society requires that new wind projects must meet U.S. Fish and Wildlife Service guidelines for minimizing impacts from wind development on birds and wildlife, and must be located outside of any “Important Bird Areas”—including the Mississippi flyway.

SWEPCO additionally agreed not to build new transmission lines associated with the Turk Plant that would cross the Nacatoch Ravines Natural Area; the Little River Bois D’Arc Management area; property currently owned by The Nature Conservancy or the Arkansas Natural Heritage Commission within Hempstead County; and property currently owned by the Hempstead County Hunting Club, which includes Grassy Lake area; or along the Kiamichi Railroad in Hempstead County.

The settlement also requires that SWEPCO test total annual particulate matter emissions to evaluate the potential for a lower emissions rate; perform an additional analysis of wastewater discharge quality during the first year of operations; perform additional groundwater monitoring at designated intervals; and conduct baseline mercury sampling tests to assess conditions prior to operation of the Turk Plant.

Finally, SWEPCO will contribute $8 million to The Nature Conservancy for land conservation in Arkansas and $2 million to the Arkansas Community Foundation, which will provide grants to support policy initiatives promoting clean energy resources and energy efficiency measures. SWEPCO also agreed to reimburse Sierra Club and Audubon for $2 million in attorneys’ fees and costs.

SWEPCO owns 73% of the $1.7 billion Turk Plant. The remainder is owned by the Arkansas Electric Cooperative Corp. (12%), East Texas Electric Cooperative (ETEC) (8%), and Oklahoma Municipal Power Authority (OMPA) (7%).

Sources: POWERnews, SWEPCO, AEP, National Audubon Society